diff --git a/docker/nginx.stage.conf b/docker/nginx.stage.conf
index d779457..e18b363 100644
--- a/docker/nginx.stage.conf
+++ b/docker/nginx.stage.conf
@@ -292,6 +292,45 @@ server {
         proxy_set_header X-Forwarded-Proto https;
     }
 
+    # ============================================================
+    # /ws/* → api-server :3721  (推論 inference WS + 既有 pairing/events/system WS)
+    #
+    # ⚠️ 為什麼必須有這條 location：
+    #   下方 catch-all `location /` 反代到 Next.js frontend (:3000)。若沒有這條，
+    #   /ws/devices/:id/inference 等所有 /ws/* 會落到 frontend → Next 沒有此 route
+    #   → 404，前端推論頁的 WS 握手斷掉。必須在 catch-all 之前用前綴 location 攔下，
+    #   導到 api-server (:3721)，該處掛 wsAuthGroup（/ws/devices/:id/inference 需 auth）
+    #   與 registerWebSocketStubs（其餘 /ws/* 目前 501 stub）。
+    #
+    # 與 /tunnel/connect 的關係：兩者是不同 path 前綴（/ws/ vs /tunnel/connect），
+    #   nginx 前綴 location 各自最長匹配、互不 shadow。/ws/ 不會吃到 /tunnel/connect。
+    #
+    # WS upgrade 三要素 + 長 timeout + buffering off，比照 /tunnel/connect。
+    #   $connection_upgrade 繼承自 http-context map（檔頭 38-41 行）。
+    #   cookie 由 proxy_pass 預設透傳（inference WS 走 cookie/session auth）。
+    # ============================================================
+    location /ws/ {
+        proxy_pass http://visiona_api;
+        proxy_http_version 1.1;
+
+        # WebSocket upgrade headers
+        proxy_set_header Upgrade           $http_upgrade;
+        proxy_set_header Connection        $connection_upgrade;
+
+        # 推論 WS 為 long-lived 串流；拉長 timeout（比照 /tunnel/connect）
+        proxy_read_timeout                 86400s;
+        proxy_send_timeout                 86400s;
+
+        # 不 buffer，避免延遲 WS 訊框
+        proxy_buffering                    off;
+
+        proxy_set_header Host              $host;
+        proxy_set_header X-Real-IP         $remote_addr;
+        proxy_set_header X-Forwarded-For   $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto https;
+        proxy_set_header X-Forwarded-Host  $host;
+    }
+
     # ============================================================
     # Next.js hashed static assets — 永久 cache
     # /_next/static/{hash}.js 等
@@ -480,6 +519,29 @@ server {
         proxy_set_header X-Forwarded-Proto http;
     }
 
+    # ── /ws/* → api-server :3721（推論 inference WS + 其餘 /ws/* stub）──
+    # 完整比照 stage-9527 block 的 /ws/ 設定：http/1.1 + Upgrade + Connection
+    # + 86400s timeout + buffering off。$connection_upgrade 繼承自 http-context map。
+    # 不會 shadow 上面的 /tunnel/connect（不同 path 前綴）。
+    location /ws/ {
+        proxy_pass http://visiona_api;
+        proxy_http_version 1.1;
+
+        proxy_set_header Upgrade           $http_upgrade;
+        proxy_set_header Connection        $connection_upgrade;
+
+        proxy_read_timeout                 86400s;
+        proxy_send_timeout                 86400s;
+
+        proxy_buffering                    off;
+
+        proxy_set_header Host              $host;
+        proxy_set_header X-Real-IP         $remote_addr;
+        proxy_set_header X-Forwarded-For   $proxy_add_x_forwarded_for;
+        proxy_set_header X-Forwarded-Proto http;
+        proxy_set_header X-Forwarded-Host  $host;
+    }
+
     # ── Next.js hashed static（內網瀏覽器用）──
     location /_next/static/ {
         proxy_pass http://visiona_frontend;